Stoker operating mechanism



Nov. 2.1, 1944.

vA. l. BRlC 2,363,389

STOKER OPERATING MECHANISM 4 sheets-sheet 1 maar L. Banca A. L. BRICE STOKER OPERATING MEGHANISM Nov. 21, 1944.

Filed Jam.A 23, 1942 4 Sheets-Sheet 2 Agnew L. Bmc

A. L. BRICE Nov. 21, l1944.

Jan. 25, 1942 `4 Sheets-Sheet 5 Patented Nov.v21, 1944 Y s'roKER OPERATING MEoHANIsM Albert L. Brice, Frederick, Md., assgnor to Fred- 'erick Iron and Steel Company, Frederick, Md.,

a corporation of' Maryland Application January 23, 1942, Serial No. 427,970

20 Claims.

This invention relates generally to improvements in stoker operating mechanisms andmore specifically to a valve-means for'varying and controlling the feeding rate of such mechanisms. y

The usual stoker system and assembly of the type here in mind comprises a hydraulically operated, reciprocating motor and a ram arranged for controlled alternate forward, or charging, and

return strokes, or movements. On the chargingI stroke the ram feeds the coal or fuel from a hopper into the retort of the boiler or heating plant and the return stroke of course brings the parts back t position for the next such operation. Controlv of the rate of fuel feed is usually obtained then by varying the frequency of the effective working strokes per unit of time, the piston of .the motor, and the ram, having pause, or dwell,

intervals between movements, and such intervals being varied in length` or time. The actual speed or rate of movement of the parts is usually independent of the frequency of lsuch movements.

My invention has as its primary object the provision of a timing or regulating valve of simple, durable and conveniently controllable construction, for thus controlling the stoker motor by varying the admission of the hydraulically actuating fluid thereto and bringing about any desired number of charging and return strokes per given unit of time. The valve thus acts to feed the-fluid from the pressure source to the motor for a desired interval and to by-pass the fluid for the desired interval to thus pause the piston and ram and control the frequency of operating movements,

Another and important object of my invention is to provide a valve of this nature which will not only vary the frequency of the operations of motor and ram but will also permit of concomitant and proportional variations in the Iactual speed of such movements to thereby make it possible to vary the fuel feeding rate over -a wide range and in selected degrees froni maximum to an absolute minimum or zero. 1

These and other more detailed and specific objects will be-made apparent in the course of the following' specification, reference being had to the accompanying drawings, in which'- Fig. lisa frontal elevation of a portion of a' tional view through the valve means of my inven tion.

Fig. 4 is a crosssection along the line 4-4 in Fig. 3 showing the valve parts as adjusted for minimum fuel feeding rate.

Fig. 5 is a similar view but showing the parts in adjusted positions for increasing the fuel feeding rate.

Fig. 6 is a cross section along the line 6-8 'in Fig. 3 showing a part of the drive chain in broken lines;

Fig. '7 is a cross section along the Fig. 3.

Fig. 8 is a detail side elevational view of the valve rotor and timing member partially disassembled. n

Fig. 9 is anv end elevational view ofthe valve showing the control wheel therefor.

Fig.v 10 is a similar view but showing a mechanism for adjusting the control wheel in accordance with temperature effects, steam pressure or the like.

Fig. 11 is a fragmentary longitudinal sectional view of the valve mechanism showing thev connection thereto of an automatic overload protection device.

Referring now more particularly and by reference characters to the drawings, `A represents generally my improved valve mechanism, the same being shown as arranged in connection with a stoker assembly B and motor and pump unit C. The latter parts and their operation will be first described in order to clarify the functioning of the valve itself.

'Ihe stoker unit B is arranged at .the front of the boiler or furnace I 0 at which is located the fuel hopper I I, said unit including a ram I2 connected by a rod I3 to the reciprocating motor I4.

line 1 1 in The parts are arranged in a housing I5 including a cylinder I6 in which the piston I1 of the motor reciprccates. Hydraulic fluid is admitted selecy tively to opposite ends of the cylinder I6 by ducts Ill-I9 under control of a reciprocating float valve 20 and pilot valve 2I, the latter being operated in conjunction with the motor and ram assembly by rod 22. AThis structure is well known in the art and need not be detailed further herein.

The unitC, also of generally conventional form, acts as prime mover orprimary power source for the Stoker and comprises a motor 23 driving a fan 24 which supplies air to the boiler or furnace. Also, through a chain drive, themotor operates a l .pump 25 of the positive displacement type which has a connection through a suction line 26 to a fluid reservoir 21, ,astrainer 28 being placed in this line as usual; 'I'he discharge 29 from the -pump is connected by a by-pas's line 30 back to the reservoir 21 and a hand controlled valve 3| is placed in thisline. Also connected across this valve SI is a pressure responsive relief valve 32.

A feed pipe or line 33 connects the discharge of the pump 25 to an inlet port 38 in the stoker motor i4, while an exhaust line 35 connects the reservoir 21 to an outlet port 36 in the motor. Obviously the pump and fan unit C may be located at any desired remote point from the stoker by suitable arrangement of the piping.

In the operation of the system as thus far described, the pump 23 taking the oil or hydraulic actuating fluid from the reservoir 21 normally will feed it through line 33 to the inlet port 34 at stoker motor I4. The valve 20 will control the admission of this fluid through one or the other of ducts I8--I9 to the cylinder I6', the valve also connecting one end of the cylinder through outlet port -36 to the exhaust line 35 back to reservoir. As here shown r(Fig. 2) the valve 20 will admit fluid to the cylinder through duct I8 while exhausting uid from the other end through duct I9. The piston I1 will thus move to the right, or forwardly towardv the furnace,

causing ram I2 to move forward beneath the' hopper II and feed a charge of fuel therefrom into the retort (not shown) of the furnace. When the piston and ram reach the limit of this movement actuation of the rod 22 will shift the duct connections to ports 34 and 36, the fluid from the pump being now admitted to the motor cylinder through duct I9 and fluid being exhausted through duct I8. The piston i1 and ram I2 will thus move rearward, or on the return stroke, back to the'position shown whereupon the valvel 20 will again reverse the fluid ow for the next charging stroke. So long as the fluid pressure and supply remains constant this intermittent reciprocating action will maintain, as will be understood.

Manual control of this operation is provided by the by-pass valve 3| which, when opened, will permit the fluid to now directly from the pump 25 backA to the reservoir 21 instead of operating the stoker motor as described above. On the other hand by partially opening and closing this valve 3| the effective fluid pressure for operating the motor may be controlled at will, thus roughly varying the effective feeding rate of fuel to the furnace.

should the ram l2 strike an obstruction, or' L other working parts become clogged for some reason, the pressure in the feed line 33 will of course build up and may then actuate the pressure responsive valve 32 causing it to open and by-pass fluid back tothe reservoir, thus prevent.- ing injury to any working parts.`

My control valve Als quency and speed ofthe charging andreturn designed to permit control of the fuel feeding rate by varying the frestrokes of the ram I2. This valve comprises a' housing or body, designated generally at 31, which is mounted asY at ,38 uponv (or near) an elec-V tric motor 39. which actuates the valve. Within this housing 'a' valve recess Il) of cylindrical shape is formed and the valve member or rotor." is

rotatably arranged therein, said rotorA beingfsel cured vby a hubr42 upon-a valve-shaft which extends outwardly through an end bf the housing. Packing 44 and a gland nut I5 are arrangedl in the housing end around the shaft to seal against the escape of iiuid thereat and the exposed end of the shaft carries a sprocket gear i6 which is connected by a chain 131 to a sprocket pinion 48 on the drivenshaft i9 of the motor 33. Obviously when thus connected the motor, will rotate the valve rotor 4I at a speed dependent on the gear reduction 50 at the motor, and the ratio of the sprockets 46 and 48, and by varying these elements the valve rotor speed :may be set at any desired value. Gears or other driving means may of course be substituted for the sprockets and chain.

The valve rotor 4I is as here shown of cupshaped form having an annular barrel portion or wall 5I and a closed end 52, whereat is located the hub 42, said end however being pierced by a series of inlet openings 53 which afford communication between the interior of the valve and an inlet chamber 54 formed in the valve housing at the end of valve recess 40 and surrounding the hub. An inlet port 55 is formed in the housing 31 opening into the chamber 54 and at its outer (here shown as lower) end is tapped to receive a pipe'iitting 56 by which connection '1s made through a pipe 51 to a point somewhere along the feed line 33 or to the discharge of the pump 25.

Telescopically and rotatably surrounding the valve rotor 4I is a timing device or shell 58 having a, thin, annular barrel or sleeve 59 which rotatably and nicely engagesthe peripheral wall of the recess 40, same being suiciently large to accommodate this sleeve. over the rotor. The shell 58 is also cup-shaped, having a closed end 60 with a hub 6I by which it is secured to an operating or adjusting shaft 62 extending outwardly through the housing end in the opposite direction to, butv on a common axis with, the aforesaid valve shaft 43. Packing 63 and a gland nut 64 here also seal around the shaft while a thrust bearing 65 braced between a shoulder 66 formed at the end of the recess 40 and the shell holds parts in alignment while permitting free movements thereof. A control or hand wheel 61 is provided on the outer end of shaft 62 as, and for a purpose, to be described.

In assembling the valve rotor lll and timing shell 58 their open ends are of course telescoped vbut the closed end of the shell is prevented from closing off the open end of the rotor by means of lugs 68 extended at spaced positions therefrom.

The valve'rotor 4I has an opening or port 69 in its barrel portion and in the same plane the shell 58 has a slot 10 which is elongated and extends substantially half way around the periphery thereof. Obviously the arrangement is such that, if the valve rotor is rotated within the timing device the opening 68 will register with the slot 10 through about one half of each revolution and will for the balance of each revolution be closed by the shell or sleeve of said timing device. Formed in the valve housing in alignment with the plane of theopening'69 and slot 10 is an exhaust port 1I tapped at its end to receive a fitting ,12'by'which a pipe 13 is connected to the valve, this pipe being in turn connected to some passes along the covered part lwill continueto be al comparatively minor afsaassc and assembly of parts therein'it is, as shown in F1828, made in twogpa'rts with,an end cap 31* secured over the end at which bearing 65 is located by meansof cap screwsl.

In the operation of the valve as thus far described it is understood that the motor 39 will rotate the valve rotor 4| within the timing shell 58 which, for purposes of example, may be adjusted and xed^so that its slot registers with the outlet channel 14 throughout its entire length as seen in Fig. 4. It is also assumed for this v example that the rotor 4l is rotated one complete turn per minute although this, as aforesaid, is subject to variation and the rotor may make any number of revolutions per time unit.

Now so long as the outlet opening 69 in the valve rotor 4I is closed by the timing shell 58 the operation of the stoker will be as previously described, the fluid flowing from the pump alternately to the ends of the motor cylinder I5 and reciprocating the piston I1 and ram I2 through charging and return strokes in sequence. How' ever, such condition will maintain only during one half revolution of the rotor Il since when this is completed the opening 69 will come into registry with the slot 10 and will remain in such communication during the remainder of Athat revolution of thev valve. Fluid under pressure from the pump is at all times present in the interior of the valvel rotor, since it flows from the pipe 51 through porti55, chamber 54 and openings 53, and during such-time as the opening 69 and slot -10 register the uid'may escape therethrough'into the channel 1I and thence through port 'Il and' pipe 13 back to the-reservoir. The result is to by-passl the fluid from pump to reservoir during one-half revolution of the valve rotor thus halting the operation of the piston l1 and ram I2 since the fluid necessary to operate same will not be furnished at this time from the positive displacement pump.

VIt will be seen therefore that iluid will be supe plied to the stoker motor for intermittent intervals and (in the example thus far discussed) will be by-passed for intervening intervals of similar lduration and the result is to cause the ram to pause, or dwell, for a period of time between each stroke', assuming that during such time as the fluid is supplied a sumcient quantity will be furnished to move the piston' through, one stroke.

'I'he duration and time length of the pauses or dwells between deliveries of fluid to the puinp may be varied by oscillating the timing shell sa to expose a varying length or area. of the slot 10 to the channel 14.. Obviously when the timing shell is turned .to move a part of the slotpast the end of thechannel 'Il (as in Fig. 5) the opening 85 will 7 ,be lilqmmlmication with the outlet port Tl for a shorterl period of time and. lthe; by-pass may) be almost or entirely'shut oil'by'properadjustments,

if so desired. Y l `It wil1"be,noted` in this connection'that even,

Vwith the slot'lll partially covered Vby being-turned -toreduce the ybye-pass timeiFig.' 5) that there will be somebyl-'pass or leakage effect as the onening 69.r traverses the'full length of the slot. Thus f while the opening 69 is passing rthat vaart ofthe slot 'Il exposed to the outlet channel 1I the fluid will be by-passed to fullest extent causing the As the opening then of the `slot there ilu-d the outlet but ram .to pause or dwell.

leakage through the slot back to l'this leakage will not be sumcientto prevent the r `building up of sumcient pressure to operate the rment oftheparts.

ram.- It'will be recognized that in constructing the valve, the shell 58 may have a wall thickness of one thirty-second of 'an inch or even less so' Athat this leakage will be very minor or of no practical eifect on the operation of the valve. On the vother hand, when theV slot 10 is completely hidden its ends may be closedA olf fromY the outlet 1l and no by-pass whatever will be provided at this point.

For so adjusting the timing shell 58 the hand wheel El is employed and it is graduated around one half of its periphery as seen in Fig. 9 to indicate corresponding positions of the shell or, more properly. of the slot 10. An index for this scale is provided by`a screw 'I6 disposedin an arm l1 extending outwardly from' the valve housing alongside thewheel and this screw may be brought to bear upon the periphery of the wheel to lock it in adjusted positions. Lugs I8 .on'the wheel also will contact the arm Il to limit the movement of the wheel to that extent which will permit movement of the slot 1U from full ex-l varying the actual speed of movement of thepiston and ram, as well as the frequency of such movements, thus enabling a nicety of control and wider range of fuel feeding variations than heretofore possible, to my knowledge.

A To this end that portion of the sleeve of the Atiming shell 58 exposed to the interior of the valve rotor by the space 'IS/which is formed be` tween the rotor barrel 5|J and sleeve end 6U (by the lugs 68) is provided with a series of fine openings or bleeder ports which are spaced in a line around about half the diameter of the sleeve and on the same side thereof having slot 10. These ports of 'course then communicate 4with the interior of the valve and they will also, when the slot 'I0 is fully exposed to the channel 14, com municate with a-passageway 8| which is both substantially semi-circular andL coextensive with channel 1I and connected thereto.

The motor cylinder is of the displacement type 'l and therefore a certain quantity of -fluid is` required to move the piston (and ram) through either charging or return strokes, no matter howslow oryhow fast this necessary quantity is sup'.

plied.' Now when thetiming shell is set to byfluid to greatest extent this required .volume of uuid would ordinarily be suppuee within a certain time, but as the opening 89 isclosed to initiate this supply and start the operation of thestoker the ports yl0 (remaining open) will leak or bleed oi! `a small quantity of the u'd from the pump back tothe ldischarge or outlet 'II thus requiring a-longer time tocomplete delivery of the requirednuid volume.v The result is to slow down the vspeed of movement of/the ravi and thus -at this setting not-o nly is the/maximum rest period between movements provided but the vspeed or. rateof such' movements is at a minimum.

on the ether hand. as the amine lshell .is afilusted to reduce the exposure-of the slnt lo'and. .thereby decrease the rest .periods of the piste-n the ports are graduallyvmfwed ,away from passageway'll and closed off decreasing the amount of fluid bled of! and thus speeding up the move- I It is thus seen that the speed of the strokes is varied proportionally to the rest intervals or length of time the ram pauses andit is thus posthis wheel may be controlled from some heat re-- sponsive source such as a steam valve, thermostat ing to requirements. As one example of such control the liandwheel'may have gear teeth 82 around its periphery as shown in Fig. and may be rotated by a gear rack` 83 lslidably supported in bearings 84 in position to lmesh with said teeth. This rack may then be connected at one end 85 to a conventional steam pressure responsive' valve or the like to vary the feed automatically accordfluid source and means for selectively applying uid under pressureto opposite sides of the piston, of a regulating valve operative to periodically relieve the 'piston of fluid pressure on either side and thereby cause it to pause at intervals in its reciprocating movements, said valve being operated independently of the movements of the piston to cause pause intervals in any position thereof.

2. In a stoker operating mechanism including a hydraulic motor piston and a fluid source for selectively supplying fluid under pressure to either side of the piston to reciprocate the same, a regulating valve having means for periodically renl5 dering said fluid source ineffective upon the piston (not shown) to increase or decrease the fuel feed-"" timed intervals independently ofthe position of ing rate in accordance with steam pressure.

. Automatic overload protection may -be built into the valve A to either displace or supplementfA the valve 32 as shown in Fig. 11. Here a tapped opening 86 is provided in the valve housing/or.

body 31 at any desired point and in communication With the chamber 54. A pressure responsive relief valve 81 of conventional form is placed in this opening and is thus subject to the fluid pressure existing in chamber 54 so that, when this pressure exceeds the setting of the valve, it will open said valve admitting fluid to a discharge pipe 88. This pipe is connected. at 89 to a-cylinder and thereby causing the piston to dwell at corresponding intervals in its reciprocating movements, and means for actuating the valve to cause said dwell intervalsv to occurV at predetermined the.J piston in its reciprocating movements.

3. In a stoker operating mechanism including a hydraulic motor having a piston and a fluid source for selectively applying :duid pressure to opposite sides of the piston and imparting reciprocatingmovements thereto, a timing valve operatively arranged to periodically by-pass the fluid and relieve the piston of fluid pressure on either side to thereby cause'the piston to dwell at intervals in its reciprocating movements, and

housing 96 secured to the valve housing 31 and communicates with a cylinder 9| therein in which is slidably mounted a plunger 92. Said plunger has a stem 93' extending to a conventional electric switch unit 94 arranged in the end of the housing 90 and from which leads a cable 95 for connection to the motor 23 driving the fluid pump 25.

an eleei'lli motor arranged to actuate the valve and to thereby control the frequency of said dwell intervals.

4. In a stoker operating 4mechanism of the character described, a hydraulic motor having a piston, a fluid source for supplying fluid `to the motor and a control means for selectively admitting fluid to opposite sides of the piston to impart intermittent reciprocating movements thereto, a

40 regulating valve operable independently of the Thus when the iiuid pressure builds up in thepressure lines to a certain point, as would occur should the ram become stalled, the flow of fluid into the cylinder 9| will urge the plunger 92 endwise to disconnect the switch 94, breaking the electrical circuit to the motor 23 and stopping the operation entirely until the ram maybe cleared motor and of the movements of the piston to periodically relieve the piston of pressure and thereby cause the piston to pause at intervals4 in such movements, and means for controlling the duration of such pause intervals.

and at the same time permitting fluid to flow into outlet 1| through a duct 96 which is opened when the plunger is thus operated. When the switch is again closed and the plunger 92 returned to normal position the little oil in the cylinder 8|- may be compressed in the pipe 86 to permit such return.

My valve as will be readily appreciated operates-.entirely independently of the position 'o1' the 5. The combination with a hydraulic stoker mechanismincluding a motor, a. pump for supplying fluid to the motor, 'and a reservoir to receiye fluid from the motor, of a regulating valve having a rotating member operative to periodically by-pass the fluid from pump Vto reservoir and thereby cause controllable dwell intervals in the operation of the motor, means separate from said motor for rotating said member, and means for varying `the-duration and frequency of said bypass periods.

motor piston and fuel feeding ram andis time f controlled to positively regulate the relative durations of fluid feed to, and by-pass around, the motor to thus regulate the frequency of theram movements strictly with regard to time intervals.

The valve may operate at constant speed with all necessary adjustments provided by the time device and no throttling means whatever ls needed i t0 control the admission of fluid to the valve to regulate the pause intervals.

It is understood ,that suitable modifications may be made in th structure as disclosed, provided such modiflcations'come,within the spirit and scope of the appended claims. Having now Atherefore fully illustrated and described my in- .ventionjwhat I claim' to be new and desire to protect by Letters Patent is:

' vals in lts reciprocating motion, and means forl. The combination with a reciprocating stolzer'. motor having a hydraulically actuated piston, a 76 ber and means fOr Connecting the fluid Supply 6. The combination with a'hydraulic stoker mechanism including a motor having a reciproeating piston, a pump for supplying fluid to the motor, and a reservoir to receive fluid from the motor, of a regulating valve having separate inlet and outlet means connected to` said pump and reservoir, a continuously rotating member operative to connect said inlet and outlet means during a part of each complete revolution of the member and thereby by-pass the fluid from pump to reservoir and cause the motor piston to dwell at interadjusting the duration of such by-pass intervals.

7. The combination with a hydraulic Stoker mechanism including a motor having a reciprocating piston, a pump for supplying fluid to the motor, and a reservoir to receivev fluid from the motor, of a regulating valve having a rotor memyhaving a ported rotor member and an outlet from the pump thereto, said valve having also an outlet means connected to the reservoir and said outlet means being elongated in the direction of movement of the rotor member, said rotor member having an opening adapted to be exposed to said outlet means to by-pass fluid from pump tok reservoir during a part of each revolution of the member, and adjustable means for varying the effective length of said outlet means to thereby adjust the duration ofthe exposure of said opening thereto during each revolution of the rotor member.

8. The combination with a hydraulic stoker mechanism including a motor having a reciprocating piston, a pump for supplying fluid tothe motor, and a reservoir to receive fluid from the motor, of a regulating valve having a, rotor member and means for connecting the Huid-supply from the pump thereto, said valve having also an outlet connected to the reservoir and said outlet being elongated in the direction of movement of the rotor member, said rotor member having an opening adapted to be exposed to said outlet to by-pa'ss'fluid from pump to reservoir during a part of' each revolution ofthe member, and adjustable means for varying the effective length of said outlet to thereby adjust the duration of the exposure of said opening thereto during eachrevolution of the rotor member, said adjustable -means being also adjustable to entirely close said outlet and prevent by-passing of *the fluid during any part ofthe revolution of the rotor member.

9. The combination with a hydraulically operated stoker motor having a piston, a .pump for supplying fluid under pressure tosaid motor to reciprocate the piston, and a 'reservoir for the fluid, of a regulating valve having a body and a rotor member and means for rotating the mem- Aber in the body, said vrotor member being arranged to receive fluid from the pump and having an opening to pass said fluid, said yalve body having an outlet opening connected to the reservoir and'adapted to communicate with the opening in'the rotor member during a part of each revolution of the said member to thereby by-pass the fluid from the pump to the reservoir, a timing device movably mounted adjacent the rotor member and having an opening, and-saidtiming device being adjustable to move its opening with respect to said outlet opening and thereby vary the eiective area of the outlet opening exposed to the opening in the rotor member.

. 10. The combination with a hydraulically operated stoker motor having a piston, a pump for supplying fluid under pressure. to said motor to reciprocate the piston, and a reservoir for the fluid, of a regulating valve having a body and a valve body and movable to vary the effective area' of the outlet channel exposed to said opening in the rotor member, and both the rotor member and movements. i

rotormember rotatable therein,said rotor lmember being arranged to receive fluid from the pump '60 timing device having annular portions telescopj ically arranged for independent rotating and adjusting movements. A

11In a stoken motor control means for a hydraulic reciprocating motor mechanism including a pump and a reservoir for supplying fluid to and receiving uid from the motor, a regulating valve means communicating with the pump and the reservoir and adapted to by-pass Vfluid therebetween at periodic intervals as said member rotates, a timing device adjustable in thevalve to vary the effective size of, or entirely close, said outlet means with respect to the rotor member to control the duration of said by-pass intervals, and a control member arranged exteriorly of the valve'for adjusting said timing device.

'A 12. In a stoker motor control meansy for a hydraulic reciprocating motor mechanism 'including a pump and a reservoir for supplying fluid to and receiving fluid from the motor, a regu' lating valve havinga ported rotor member and an outlet means communicating with the pump andthe reservoir and adapted to by-pass fluid therebetween at periodic intervals as said member rotates, a timing device adjustable in the valve to vary the area of said outlet means exposed to the rotor member and thereby to control the duration of said by-pass intervals, a control member arranged exteriorly of the valve and connected to said timing device for adjusting the same, and means connected to said control vmember' for adjusting the timing device from aremote point.

13. Ina Stoker motor control mechanism fo a hydraulic motor having a reciprocating piston, a pump for supplying fluidto the motor, and a reservoir; a v alve adapted to periodically by-pass fluid from pump to reservoir to dwell the piston at intervals, means for varying the duration and frequency of such dwell intervals, and said valve also having means for varying the speed of the reciprocating movements of the piston in accordance With variations in the frequency of such 14. In a stoker motor control mechanism for a hydraulic motor'having areciprocating piston, a pump for supplying fluid to the piston, and a reservoir; a regulating valve for regulating the effective admission of -fluid to the motor and operative to render said motor piston inactive at dwell intervals of variable duration and to therevalve connected between the pump and reservoir y and having means for periodically by-passing the fluid providing for direct flow from pump to reservoir and rendering the motor inoperative, tim- 'ing means for varying the duration of said `bypass intervals, and said valve also having means for leaking a variable, comparatively small quantity of fluid from pump to reservoir when the motor is operating to thereby control the speed of movement of the piston.

16. The combination with a hydraulic stoker motor, a pump for supplying operating fluid to the motor, and a fluid reservoir, of a regulating valve including a rotor member having an opening connected to the pump, said valve having said opening to thereby vary the duration of suoli dwell intervals, and said timing device also having relatively smaller openings adapted to leal?. off a portion of the fluid from pump to reservoir betweenl such dwell intervals, said smaller open-z ings being arranged to be progressively closed as the timing device is adjusted to decrease the duration of said dwell intervals.

17. 1n a hydraulic Stoker motor operating mechanism, a pump for supplying operating iuid to the motor, an electric motor for operating the pump, a fluid reservoir, a regulating valve connected between pump and reservoir and adapted to by-pass fluid :for direct rlow therebetween at adjustable intervals to thereby halt the operation of the motor at corresponding intervals, an overn load protection device arranged on the regulate ing valve and including a cylinder, a rpressure responsive valve for admitting uid to said cylinder from the pump, a `plunger in the cylinder adapted to be actuated by iluid entering the same, and an electric switch unit controlling the oper- 'ation of the pump motor and adapted to be opened when the iuid enters said cylinder.

18. A regulating valve for a stolzer motor mech anism including a pump for supplying uid to the motor and means to receive fluid from the motor, comprising a valve body having an outlet substantially half way around the rotor and thereby adapted to register with the opening in the rotor during approximately one-half of each revolution thereof, and a timing device surroundaeoasee ing the rotor and having a slot adapted to con neet the opening in the rotor with the outlet to control the uid flow therebetween, the said timing device being rotatable about the rotor and the said slot being of substantially the same length as the outlet.

i9. A valve for a Stoker motor mechanism including a pump for supplying uid to the motor and means for receiving fluid from the motor, comprising a valve body having a recess, a hollow valve rotor mounted for rotation in the recess and having an inlet connected to receive fluid from the pump, the said body having an outlet in the wall of the recess communicating with the rotor and connected to the fluid receiving means, the said rotor having a discharge opening adapted to register with the outlet during a part of each revolution of the rotor, and a timing sleeve rotatably surrounding the rotor within the recess and having an opening adapted to be moved with respect to said outlet to thereby vary the flow from the discharge opening and through the outlet While the latter is exposed to the opening in the rotor during each revolution thereof.

2o. A valve :for a uid actuated stolzer motor for periodically bywgassing the uid and causing the motor to dwell, comprising a body having fluid inlet and outlet means, a valve rotor mount-1 ed for rotation in the body and having a port adapted to connect the inlet and outlet means during a part of each revolution of the rotor, and a timing device operatively arranged adjacent the rotor for varying the angular part of each complete revolution during which. the rotor port is effective to 'oy-pass the iluid between the said inlet and outlet means.

ERT L lBRlCE. 

